Slaterocoris argenteus Kelton

Slaterocoris argenteus Kelton Figures 12, 28I–L, 29E–G; plate 1; map 5

Slaterocoris argenteus Kelton, 1968: 1134: fig. 21 (orig. desc.); Knight, 1970: 241, fig. 31 (disc.); Schuh, 1995: 197 (catalog).

DIAGNOSIS: Distinguished from S. simplex —a species that shares the completely black coloration, striate frons, and dense, moderately long, silvery sericeous setae—by the absence of adpressed setae near the claval suture. Within the S. argenteus -group, recognized by the conspicuous sexually dimorphic hemelytron (pl. 2), longer antennal segment II (1.13–1.408, 0.98–1.21 ♀) and male genitalia with a pointed medial spine of the right paramere and longer ventral lobe of the endosomal spicule (fig. 29E) as compared to S. digitatus with shorter male hemelytron length (pl. 2), somewhat shorter length of antennal segment II (1.00–1.108, 0.91– 1.00 ♀), and shorter distal portion of the ventral lobe (fig. 29H). Although the black coxae will usually discriminate S. argenteus from S. argenteoides, where the coxae are sometimes infuscate, the shorter, untwisted body of the right paramere (fig. 28I–L) and the smaller apex of the dorsal lobe in the endosomal spicule (fig. 29E) are diagnostic. The hemelytron of the female is not as flattened and is shorter than in S. argenteoides (pl. 1), whereas the curvature of the costal margin is not as great as in S. digitatus (pl. 2).

REDESCRIPTION: Male: Body moderately large, elongate, length 4.30–5.40, width 1.70– 2.10 (pl. 1). Coloration, vestiture, and structure as in the S. argenteus- group description with the following specific features: GENITALIA: Endosomal spicule: Dorsal lobe marginally serrate on distal one quarter, gradually attenuate distally; ventral lobe distal portion shorter than basal portion, gradually attenuate, moderately serrate, pointed (fig. 29E). Right paramere: Relatively short; arrangement of spines variable; medial spine sometimes pointed; with two or three short apical parallel spines on same plane with body of paramere (fig. 28I–L). Left paramere: Shaft long, in apical view, slightly longer than paramere body in lateral view (fig. 29G).

Female: Short, ovate, length 3.40–3.95, width 1.80–2.10 (pl. 1). STRUCTURE: Costal margin short, conspicuously curved. GENITALIA: As in species group except: Right first gonapophyses: Lateral surface small. Second gonapophyses: Anterior medial surface slightly convex. Interramal sclerite: Dorsomedial region flat, not produced anteriorly. Interramal lobe: Dorsomedial margin with short process; ventral margin with long projection and concave anterior surface.

HOSTS: Beyond the notation of Asteraceae, no other host-plant information is available.

DISTRIBUTION: 69 specimens from 8 collection events with northern specimens in the Central Plateau of Durango collected in July and those from further south in the northern edge of the Sierra Transvolcanica collected in September (map 5).

DISCUSSION: The distribution as currently known appears to be separated into northern and southern populations. The male genitalia of several individuals from each end of the range showed similar variation (fig. 28I–L). Further collecting may reveal that S. argenteus is more widely distributed in the Central Plateau of Mexico.

HOLOTYPE: MEXICO: Durango: 6 mi E of Durango [24.83336 N 104.737286 W, 1981 m], 24 Jul 1964, L.A. Kelton, 18 (AMNH _ PBI 00111760) (CNC).

OTHER SPECIMENS EXAMINED: MEXICO: Durango: 6 mi E of Durango, 24.83336 N 104.737286 W, 1981 m, 24 Jul 1964, L.A. Kelton, paratype, 18 (00121773), 1♀ (00121774) (CAS), paratypes, 58 (00111761– 00111764, 00111766), 1♀ (00111765) (CNC), paratype, 18 (00118613), 1♀ (00118614) (TAMU). 25 mi S of Durango on Hwy 45, 24.462626 N 104.73836 W, 24 Jul 1964, L.A. Kelton, paratypes, 28 (00111767–00111768), 2♀ (00111769–00111770) (CNC). 40 mi S of Durango, 23.766196 N 103.863926 W, 30 Jul 1964, L.A. Kelton, paratype, 18 (00111771) (CNC). 41 mi NE of Durango, 24.405086 N 104.243526 W, 1998 m, 28 Jul 1956, R.E. Beer and party, Light Trap, 18 (00117800) (KU). Mexico: Encinillas [sic Encinello], 20.156 N 99.756 W, 2453 m, 02 Sep 1969, L.A. Kelton, 18 (00111725), 2♀ (00111726–00111727) (CNC). Jilotepec, 19.952776 N 99.534726 W, 02 Sep 1969, L.A. Kelton, 138 (00111688– 00111700), 24♀ (00111701–00111724) (CNC). Michoacan: Lago de Cuitzeo [Cuitzeo del Porvenir], 19.98336 N 101.156 W, 1900 m, 06 Jul 1947, T.H. Hubbell, 2♀ (00127328– 00127329) (UMMC). Queretaro: Queretaro, 20.60006 N 100.383336 W, 1868 m, 04 Sep 1969, L.A. Kelton, Asteraceae, 48 (00111750– 00111753), 6♀ (00111754–00111759) (CNC).